1. Technical Field
This invention relates generally to building construction materials and, more particularly, to an apparatus for fabricating precast concrete wall sections.
2. Discussion of the Related Art
It is known to provide prefabricated concrete wall sections for use in, for example, constructing building basements. In general, prefabricated or precast concrete wall sections are generally manufactured using a fixed dimension form. In one known approach a uniform thickness, fixed length wall is provided. In another known approach, a substantially unitary precast concrete wall section is provided having vertically-extending side-edge flanges and a plurality of spaced rib portions separating intervening cavities. Yet another known approach provides a variable length, but fixed, uniform thickness wall section. There are a wide variety of other variations found in the art.
There are several advantages, in general, to the use of precast concrete sections, most notably the increased dimensional control obtained by the manufacturer of the section by the manufacture thereof in a controlled setting. However, there are several shortcomings associated with the known approaches taken in the art for making such wall sections.
One disadvantage pertains to the fixed dimension type form. Since the form is dimensionally fixed, only one size of concrete wall section may be made therefrom. This results in an increased number of forms required to produce the wide range of sizes needed to accommodate various construction requirements. Moreover, since space limitations dictate that not all of the forms can be setup and available for use at all times, only the most frequently used forms are setup. This results in an increased inventory, since the operator generally makes a number of the seldom-needed precast concrete sections, some for later use. Maintaining large inventories of concrete wall sections is undesirable.
While the variable length, uniform thickness type wall section referred to above overcomes some of these shortcomings, the uniform thickness of the wall is undesirable because it leads to increased weight due to unnecessary usage of concrete (i.e., compared to the cavity/rib type wall section). There are substantial difficulties in producing a variable length, cavity/rib type wall section, since if the desired length causes a side end of the wall to fall in the middle of a cavity, such side end will have an insufficient wall thickness, making it structurally unusable.
There is therefore a need to provide an improved precast concrete wall section, and a system for making the same, that minimizes or eliminates one or more of the shortcomings as set forth above.
The present invention reduces or eliminates large inventories of precast concrete wall sections having a wide variety of dimensions and provides a variable length, rib cavity type wall section. In accordance with the present invention, an adjustable casting tool is provided for forming various-sized concrete wall sections. The casting tool includes a base, one or more pan members, a pair of opposing sidewalls, and first and second opposing bulkheads. The base is configured for orientation in a horizontal plane and has an upper surface. The base further includes a plurality of receiving locations spaced apart along a first axis. Pan members are attached at selected receiving locations. The remaining space on the base unoccupied by pan members defines a remainder length, which is taken along the first axis. The pan members are raised relative to the base to form corresponding cavities in the wall section. The sidewalls are disposed proximate the upper surface of the base. Each of the sidewalls has a substantially vertical first position. The opposing bulkheads are also disposed proximate the upper surface. Each of the bulkheads also has a substantially vertical first position. The first and second bulkheads are arranged to abut the pair of opposing sidewalls such that the pair of sidewalls, the first and second bulkheads, and the upper surface (including the raised pan members) define a form for making the precast concrete wall section. In accordance with the present invention, the first bulkhead is configured for movement along the first axis through the remainder length so as to vary a first dimension of the form.
In effect, pan member may be added to obtain a rough adjustment of the desired length, while the first bulkhead is moveable through the remainder length to obtain a fine adjustment of the desired length. Thus, the present invention eliminates the need for a wide variety of forms to accommodate varying dimensions. In addition, the invention eliminates the need to stock a large inventory of concrete wall sections of variable sizes. The adjustable casting tool provides the means to adjust a first dimension, for example, the length of the concrete wall section. Thus, desired lengths may be formed to accommodate building requirements on an xe2x80x9cas neededxe2x80x9d basis.
In another embodiment, the height of the form is adjustable.
In yet another aspect of the present invention, a precast concrete wall section is provided. The wall section includes a main body formed substantially of concrete having a preselected height and length. The main body includes a header, a footer, a pair of end sections, at least one rib, and a plurality of cavities. The header laterally extends substantially the preselected length of the main body, as does the footer. The end sections are vertically extending between the header and the footer, and are disposed at opposing side ends of the main body. The rib is also vertically extending between the header and the footer and is laterally spaced from both end sections. The cavities are formed between the header, the footer, the end sections and the rib. The rib separates the cavities and may be used as a xe2x80x9cstudxe2x80x9d during construction. A first thickness of the main body in the cavities is less than a second thickness of the main body associated with any one of the header, the footer, the end sections, and the rib.
According to the invention, one of the end sections is longer than the other one of the end sections. This provides increased strength, for example, when forming corners using two wall sections. In further embodiments, the header includes at least one of a support beam blockout feature, a window blockout feature, and a reveal feature.
Other objects, features and advantages of the present invention will become apparent to one skilled in the art from the following detailed description and accompanying drawings illustrating features of this invention by way of example, but not by way of limitation.